Boulder County health officials Wednesday confirmed four cases of West Nile virus in adults.

Two of the patients live in Lafayette, one lives in Boulder and another lives in Longmont, according to a news release issued by Boulder County Public Health.

Each patient reportedly has suffered from symptoms including fever, headache, chills, body aches, joint, bone and muscle pain, and loss of appetite, officials say. All of the patients reported that they started experiencing symptoms in late July.

West Nile virus is passed on to humans by the bite of an infected mosquito, with symptoms usually appearing three to 14 days after exposure. The infection is often mild but can become more serious, causing encephalitis -- or swelling of the brain -- meningitis, loss of vision, coma, tremors or even death.

There is no known cure or human vaccine for the virus, but health care providers can make patients more comfortable and help them recover more quickly.

Of the cases announced Wednesday, three patients are recovering at home, according to Boulder County Public Health, while one, the patient from Longmont, has been hospitalized.

Boulder County saw just one confirmed case of West Nile virus in 2012, according to statistics kept by the Colorado Department of Public Health and Environment. Local health officials indicated they see the four cases confirmed Wednesday as a wake-up call.

"This is a reminder to all of us that West Nile virus is still a risk," Carol Helwig, Boulder County Public Health communicable disease control program coordinator, said in the new release. "We all still need to take steps to protect ourselves and our families."

After local testing revealed a high index of West Nile virus positive-testing mosquitoes, Longmont has conducted citywide mosquito spraying.

The Longmont City Council voted unanimously last month to spend $50,000 on the spraying efforts, which drew complaints from some residents who asked that the sprayers be shut off as they passed their homes.

Lafayette and Erie also called in contractors to spray for mosquitoes last month, though those efforts were confined to specific areas. Parts of unincorporated Boulder County have also been sprayed this year.

There have been 22 confirmed cases of West Nile virus in Colorado this season and 174 nationwide, according the Boulder County Public Health. Seven people have died of the illness this year.

New coordinator pushes Buffs to work, play at level he expectsJim Leavitt has discovered this much about his new defense at Colorado: He has some talent with which to work, but his players need to put it in another gear. Full Story

New coordinator pushes Buffs to work, play at level he expectsJim Leavitt has discovered this much about his new defense at Colorado: He has some talent with which to work, but his players need to put it in another gear. Full Story